On Sat, Mar 15, 2014 at 11:26:27AM +0000, Duncan wrote: > Chris Samuel posted on Sat, 15 Mar 2014 17:48:56 +1100 as excerpted: > > > $ sudo smartctl --identify /dev/sdb | fgrep 'Trim bit in DATA SET > > MANAGEMENT' > > 169 0 1 Trim bit in DATA SET MANAGEMENT command > > supported > > $ > > > > If that command returns nothing then it's not reported as supported (and > > I've tested that). You can get the same info with hdparm -I. > > > My puzzle now is that I have two SSD drives that report supporting NCQ > > TRIM (one confirmed via product info) but report only supporting SATA > > 3.0 not 3.1. > > My SATA 2.5 SSDs reported earlier, report support for it too, so it's > apparently not SATA 3.1 limited. (Note that I'm simply grepping word > 169, in the command below. Since word 169 is trim support...) > > sudo smartctl --identify /dev/sda | grep '^ 169' > 169 - 0x0001 Data Set Management support > 169 0 1 Trim bit in DATA SET MANAGEMENT command supported > > Either that or that feature bit simply indicates trim support, not NCQ > trim support.
Mmmh, so now I'm confused. See this: === START OF INFORMATION SECTION === Device Model: INTEL SSDSC2BW180A3L Serial Number: CVCV215200XU180EGN LU WWN Device Id: 5 001517 bb28c5317 Firmware Version: LE1i User Capacity: 180,045,766,656 bytes [180 GB] Sector Size: 512 bytes logical/physical Rotation Rate: Solid State Device Device is: Not in smartctl database [for details use: -P showall] ATA Version is: ACS-2 (minor revision not indicated) SATA Version is: SATA 3.0, 3.0 Gb/s (current: 3.0 Gb/s) Local Time is: Sat Mar 15 15:49:06 2014 PDT SMART support is: Available - device has SMART capability. SMART support is: Enabled polgara:/usr/src# smartctl --identify /dev/sda | grep '^ 169' 169 - 0x0001 Data Set Management support 169 0 1 Trim bit in DATA SET MANAGEMENT command supported This is a super old SSD from 3 years ago. Clearly it can't support synchronous dicard, right? Yet, deleting a kernel tree also takes 1.5 seconds: polgara:/usr/src# time rm -rf linux-3.14-rc5/ real 0m1.441s user 0m0.048s sys 0m1.352s So maybe it's not the data level, but just the value of 169? Either way, this SSD is more than 2 years old, maybe 3 actually. Marc -- "A mouse is a device used to point at the xterm you want to type in" - A.S.R. Microsoft is to operating systems .... .... what McDonalds is to gourmet cooking Home page: http://marc.merlins.org/ | PGP 1024R/763BE901 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html